Surgical saw blade having at least one pair of opposed teeth shaped as right triangles

ABSTRACT

A cutting saw blade for use with an oscillatory power tool used in surgical bone cutting procedures including a blade having a distal end provided with teeth whose tips are located on a tangent line perpendicular to the long axis of the blade. The teeth are configured substantially as right triangles with their hypotenuses facing either towards the center of the blade or away from the center of the blade. A central tooth can be optionally provided. The surgical saw blade may have a distal end having at least one pair of teeth configured to be adjacent to each other and each of the pair of teeth is configured as a right triangle each having a hypotenuse which is oriented at least one of towards and away from the centrally positioned long axis.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a Divisional Application of pending U.S. patentapplication Ser. No. 10/826,209 filed on Apr. 16, 2004, which is aContinuation-in-Part of U.S. patent application Ser. No. 10/071,382filed on Feb. 6, 2002, issued as U.S. Pat. No. 6,723,101 on Apr. 20,2004, which is a Continuation of U.S. patent application Ser. No.09/499,803 filed on Feb. 8, 2000, issued as U.S. Pat. No. 6,503,253 onJan. 7, 2003, which is a Continuation of U.S. patent application Ser.No. 08/153,871 filed on Nov. 16, 1993, issued as U.S. Pat. No. 6,022,353on Feb. 8, 2000, which is a Continuation of U.S. patent application Ser.No. 07/707,903 filed May 30, 1991, abandoned.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO A “MICROFICHE APPENDIX” (SEE 37 CFR 1.96)

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The following invention relates generally to instrumentalities forcutting bone during surgery. More particularly, the instant invention isdirected to a saw blade adapted to be operatively coupled to anoscillatory (or sagittal) surgical power tool which reciprocates thecutting blade back and forth about a small arc. In the preferredembodiment, the surgical saw blade may have a distal end having at leastone pair of teeth configured to be adjacent to each other and each ofthe pair of teeth is configured as a right triangle each having ahypotenuse which is oriented at least one of towards and away from thecentrally positioned long axis.

2. Description of the Prior Art

One of the most vexing problems that surgeons face when using surgicalbone saws is the tendency of the saw to “kick” i.e., become caught uponthe bone being cut by the point of the saw tooth. Another form ofkicking occurs where the kerf has the same contour as the blade which isdue to the fact that the cutting surface (i.e., teeth) lies on the sameradius as the radius of tool rotation. In this scenario, all teeth grabnearly at the same time. This causes the saw apparatus to rotate aboutthat point, transmitting a rotational force back through the saw and tothe surgeon. This kicking or grabbing that occurs causes a loss ofaccuracy in the cut from the sudden, unpredictable movements of the sawand induces increased fatigue of the surgeon because of the greatertension that the surgeon must maintain in his hands and arms inanticipation of receiving this kicking or grabbing motion.

Another problem noted in existing blades involves the tendency of thesaw to initially wander rather than to form a kerf. One reason for thisinvolves the nature of oscillatory cutter blades. The handle portion ofthe saw remains stable because it is in the surgeon's control and remotefrom the cutting. However a blade (having a proximal end mounted intothe oscillatory power tool) moves at a distal end that scribes an arc ofa circle. Most surgical cutting saw blades have teeth on the distalextremity which are also oriented in an arc of constant radius.Especially when that arc has a geometrical center which coincides withthe center of oscillatory motion, the bone to be penetrated is normallyinitially addressed by only one active cutting tooth in the series ofteeth that resides on the arc, and as the blade completes its outwardmotion many teeth come into contact simultaneously. With several teethcontacting the bone, there is a greater tendency of the saw blade tokick and wander. The effect is even more pronounced when the bladeteeth's center of arc is between the oscillatory center of the powertool and the blade's distal end.

Another problem involves the non-aggressive nature of prior art blades.Even when more than one tooth contacts the bone, it is primarily due tothe manipulation of the blade by the surgeon. The effect is thatadjacent teeth do not effect progressive cutting and therefore makebinding and kick back more likely.

Moreover, once the kerf has formed, several other problems attend thecutting process. For one thing, substantially all the saw's teethtraverse along the entire extent, of the kerf. This decreases theaggressiveness of the cutting action as the cutting action is anabrading one rather than chipping. The teeth reside within the kerf fora longer period of time and tend to naturally generate more heat thanhad they been allowed outside the kerf. In addition, not having theteeth exit the working surface periodically tends to leave the chips ofbone that have been abraded by the teeth to remain between the teeth.Lack of efficient chip removal is recognized as one cause of excessiveheat generation. In surgical situations, such unwanted heat generationis undesirable because of thermal necrosis which damages bone structureadjacent to the cut.

The following documents reflect the state of the art of which applicantsare aware and are tendered herewith to discharge the applicants'acknowledged duty to disclose relevant prior art of which they areaware. However, it is respectfully stipulated that none of these priorart teachings anticipate when considered singly or render obvious whenconsidered in any conceivable combination the nexus of the instantinvention as particularly detailed hereinafter.

INVENTOR PATENT NO. ISSUE DATE Carroll 2,455,655 1948 Tuke 3,905,1051975 Winter 3,905,374 1975 Bent 3,943,934 1976 Mongeon 4,386,609 1983Arnegger 4,513,742 1985 Arnegger 4,584,999 1986

CATALOG TITLE Micro-Aire.sup.tmCatalog “Accessories - Orthopedic PowerInstrument System” Stryker* Surgical Catalog “Cutting Accessories Guide”Hall Surgical Catalog “Hall Quality Saw Blades for Stryker and 3M”

None of the prior art explicitly recognizes the value in having theteeth on an oscillatory cutter placed substantially on a tangent whichis perpendicular to a radial line extending from the center of the powertools cutting axis that bisects the arc of travel within which the bladetravels.

BRIEF SUMMARY OF THE INVENTION

The instant invention is distinguished over the known prior art in amultiplicity of ways.

In its essence, the blade of the instant invention takes intoconsideration the natural tendencies at play when a surgeon is cutting abone with an oscillatory saw. In general, the natural tendency is tomake a plunge type cut, i.e., move the tool and blade in a singledirection, plunging the saw in the bone for cutting. The direction offorce imposed by the surgeon is intuitively coaxial with the long axisof the saw and blade. When viewed in this light, it should be clear thatprior art cutting blades having curved cutting heads will cause the tipof the tooth to either wander or kick. The instant invention, however,addresses the bone to be cut in a manner which reduces fatigue by thesurgeon and vibration or impulses generated during the cutting process.

More specifically, when a tooth profile parallels tangents to the arc oftravel of the oscillatory cutter, the bone to be cut sees approximatelyone tooth at a time when the surgeon is making a plunge into the bone.Actually, the contact starts at the center and moves outwards. In thisway, there is less pulsed vibration, there is a lower tendency of thesaw to kick by having one tooth engage the bone and rotating thereabout,and there is better bone chip evacuation which reduces the operatingtemperature of the saw adjacent the cut.

One attribute of the instant invention is that each working toothprogressively cuts more material than the previous working tooth so thatcollectively, all teeth contacting the bone to be cut make progressivecontributions.

Three types of saw blades illustrative of these phenomena are disclosedin the instant application. One blade includes a series of cutting tipsall oriented in a linear plane and the teeth which support these tipsall have the general configuration of isosceles triangles.

A second form of cutting tool is disclosed in which the tips of all ofthe teeth are also substantially in a horizontal plane, but the teethwhich support these tips have a different contour from the firstversion. A central-most tooth may be in the form of an isoscelestriangle as in the first invention form, but the remaining teethdisposed outboard the central isosceles tooth are all substantiallyright triangles in which the vertical leg of the right triangle isoriented adjacent the central isosceles tooth and the hypotenuse portionis outboard from the central isosceles tooth. This provides a positiverake, and the most aggressive cut as the blade cuts progressively fromthe inside out.

A third form of cutting blade is shown in which the right triangles ofthe second version have been oriented 180° so that the hypotenuse ofeach cutting tooth faces the center of the cutting blade. In practice,the “right” triangles may be “near” right triangles with the includedangle greater than 90° for an aggressive cut. The cutting occurs on thetip of the hypotenuse. Also, there is a central isosceles void providedwhere there had been the central tooth of the second invention form.

In an alternative, the cutting blade may have a distal end having atleast one pair of teeth having tips configured to be adjacent to eachother and positioned one on each side of the elongated central axis ofthe blade. Each of the pair of teeth is configured as a right triangleeach having a hypotenuse which is oriented at least one of towards andaway from the centrally positioned long axis.

Accordingly, it is the primary object of the present invention toprovide a novel and useful cutting saw blade for use in surgery.

A further object of the present invention is to provide a device ascharacterized above which minimizes the degree of heat buildupassociated with the surgical cutting to reduce the thermal necrosis thatattends cutting bone.

A further object of the present invention is to provide a device ascharacterized above which minimizes the backlash and kick that thesurgeon experiences when using traditional blades.

A further object of the present invention is to provide a device ascharacterized above which can be relatively economically manufactured,lends itself to mass production techniques and is extremely durable inconstruction.

A further object of the present invention is to provide a device ascharacterized above which cuts aggressively and has a tendency toinitially form a kerf, and self centers itself and cuts through the bonequickly within which the blade will reside.

A further object of the present invention is to provide a surgical sawblade having a centrally positioned long axis, a proximal end configuredto couple to a surgical bone saw and a distal end having at least onepair of teeth having tips for cutting bone which are configured to beadjacent to each other and wherein one of the pair of teeth isconfigured as a right triangle with a hypotenuse which is oriented atleast one of towards and away from the centrally positioned long axisand the other of the pair of teeth configured as a right triangle with ahypotenuse which is oriented in a direction opposite to the hypotenuseof the one of the pair of teeth.

A further object of the present invention is to provide a surgical sawblade having at least one pair of teeth having tips for cutting bonewhich are configured to be adjacent to each other and wherein the distalend has extending from each of the pair of teeth at least one additionaltooth having a tip for cutting bone which is substantially identicallyshaped as a right triangle including a hypotenuse and an angle oppositethe hypotenuse with a hypotenuse which is oriented in the same directionas the hypotenuse of the adjacent tooth defining the pair of teeth andwherein the tips of all of the teeth are arrayed substantially on atangent perpendicular to the centrally positioned long axis.

A further object of the present invention is to provide a surgical sawblade having between at least two additional teeth having tips and up tofive additional teeth having tips for cutting bone all of which aresubstantially identically shaped as a right triangle including ahypotenuse and an angle opposite the hypotenuse with a hypotenuse whichis oriented in the same direction as the hypotenuse of the adjacenttooth defining the pair of teeth and wherein the tips of all of theteeth are arrayed substantially on a tangent perpendicular to thecentrally positioned long axis.

Viewed from one vantage point, it is an object of the present inventionto provide a surgical cutting saw blade for penetrating bone when theblade is operatively coupled to an oscillatory power tool. The saw bladehas a proximal end and a distal end. The proximal end has means forattachment to the oscillatory power tool for driving engagement thereby.The distal end has a plurality of cutting teeth oriented such that,initially, the outboard teeth contact the bone to be cut to therebyprovide better tracking of the saw when forming a kerf in the bone, andthe teeth then cut sequentially as the kerf begins to form to providefaster, aggressive cutting and lower temperature cutting throughefficient chip removal.

These and other objects will be made manifest when considering thefollowing detailed specification when taken in conjunction with theappended figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of the apparatus according to one embodimentof the present invention;

FIG. 2 is a top plan view of a second embodiment similar to FIG. 1;

FIG. 3 is a detail of the distal end of the embodiment shown in FIG. 2;

FIG. 4 shows the distal end of a third embodiment;

FIG. 5A diagrammatically shows the blade of the present invention posedto begin a cut;

FIG. 5B shows the FIG. 5A blade having progressed partially through acut;

FIGS. 6A and 6B parallel FIGS. 5A and 5B respectively but show priorart;

FIG. 7 is a top plan view of another embodiment of the present inventionwherein the saw blade has a tooth structure comprising a center toothdefining a “whale shaped” tooth formed of two opposing right triangleshaving tips and located to have the axially extending centerline of thesaw blade passing therethrough followed on each side thereof with fiveidentically shaped teeth having tips formed of a right triangle havingtips and located to have the hypotenuse thereof extending at least oneof towards and away from the center line;

FIG. 8 is a top plan view of yet another embodiment of the presentinvention wherein the saw blade has a tooth structure comprising acenter tooth defining a “whale shaped” tooth formed of two opposingright triangles having tips and located to have the axially extendingcenterline of the saw blade passing therethrough followed on each sidethereof with four identically shaped teeth having tips formed of a righttriangle having the hypotenuse thereof extending at least one of towardsand away from the centerline;

FIG. 9 is a top plan view of still yet another embodiment of the presentinvention wherein the distal end of the saw blade has a tooth structurecomprising a center tooth defining a “whale shaped” tooth formed of twoopposing right triangles having tips and located to have the axiallyextending centerline of the saw blade passing therethrough followed oneach side thereof with two identically shaped teeth formed of a righttriangle having the hypotenuse thereof extending at least one of towardsand away from the centerline and the proximal end of the saw blade has ahub structure configured for being driven by a driving member havingdriving pins; and

FIG. 10 is a top plan view of yet still another embodiment of thepresent invention wherein the distal end of the saw blade has a toothstructure comprising a center tooth defining a “whale shaped” toothformed of two opposing right triangles having the axially extendingcenterline of the saw blade passing therethrough followed on each sidethereof with two identically shaped teeth formed of a right trianglehaving the hypotenuse thereof extending at least one of towards and awayfrom the centerline and the proximal end of the saw blade has a hubstructure configured for being driven by a driving member having asingle driving pin.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures, wherein like reference numerals denote tolike parts throughout the various figures, reference numeral 10 isdirected to the straight saw blade according to one form of theinvention, reference numeral 30 is directed to the reverse opposed bladeaccording to the second form of the invention and reference numeral 40is directed to the outwardly opposed blade according to a third form ofthe invention.

The straight saw blade 10 of FIG. 1 and according to the presentinvention includes a distal end 8 upon which a plurality of teeth 2 arepositioned and a proximal end 12 which is adapted to coact with andattach to an oscillatory (or sagittal) surgical power tool (not shown).

More specifically, the proximal end 12 has a somewhat bulbous terminus22 that includes a slot 14 running along the long axis A of the sawblade 10. In addition, a plurality of holes 16 circumscribe portions ofthe slot adjacent the bulbous terminus 22 to further facilitateinterconnection between the saw blade 10 and the oscillatory power tool.

The blade 10 includes a shank 18 interposed between the proximal end 12and the distal end 8. In general, the shank 18 is formed fromsubstantially flat stock material having side edges 20 a which, as shownin FIG. 1, are tapering so that the blade narrows as it goes from thedistal end 8 to the proximal end 12.

The distal end 8 of the blade 10 includes, coincident with the long axisA of the blade 10, a diamond shaped cutout 24 having radiused apices atthe corners of the diamond. The diamond shaped cutout is oriented suchthat two of the four radiused apices are coincident with the long axis Aof the shank 18. In addition to providing a lighter blade, the diamondshaped orientation tends to assist in tooth profiling duringfabrication.

As mentioned, the distal end 8 of the saw blade 10 includes a pluralityof teeth 2 disposed on the distal end of the blade 10 remote from theslot 14. Each of the teeth 2 is formed from two sides 4, which coalesceto form the tooth 2. The area of coalescence is defined as tip 6.

As shown in FIG. 1, each of the teeth 2 are formed as isoscelestriangles having all tips 6 located on a line T which is tangential tothe oscillatory rotation R shown in FIG. 1. Thus, the tips 6 terminateon the tangent line T which is perpendicular to the longitudinal axis Aof the cutting blade 10. This is measured when the blade is at an anglewhich is one-half its maximum arc swing. Typically, an oscillating powertool swings through an arc of 2° to 8° and at speeds ranging from 10,000cycles per minute to 30,000 cycles per minute.

In a preferred form of the invention, attention is now directed to FIG.2 which shows a variant of that which is shown in FIG. 1. Tooth detailsfor FIG. 2 are shown in FIG. 3. As shown in FIG. 2, the blade 30 isgenerally characterized as one which is “reverse opposed” i.e., having aplurality of teeth which are inwardly directed such that when acenterline CL is drawn through the long axis of the blade, two sets ofinwardly directed teeth will be evidenced. Those teeth which are to oneside of the centerline face those teeth on the other side and areopposed to each other.

The blade 30 also shows that the proximal end 12 includes a bulbousterminus 22 as described with respect to FIG. 1 but in addition to theslot 14 running parallel to the long axis or center line CL, a pair ofrecesses 15 extend inwardly on linear portions of the U-shaped slot foradditional attachment to the oscillatory power tool. Moreover,additional holes 16 circumscribe the U-shaped slot 14 to provideadditional retention and drive points when connected to the oscillatorypower tool.

The shank 18 is formed from flat stock material whose side edges 20 bextend from the distal end 8 to the proximal end 12 but, unlike FIG. 1,these side edges 20 b are parallel.

With respect to FIG. 3, certain details of the tooth configuration canalso now be best appreciated. As shown, the centerline reflects that onecentral tooth 32 has an apex or tip coincident with the centerline CL ofthe long axis of the blade 30. Thus, the central tooth 32 is depicted asforming a substantially isosceles triangle similar to the teeth 2 shownin FIG. 1. However, the centerline CL serves as a line of demarcationbetween the left lateral side of blade 30 and the right lateral side ofblade 30. As shown, the left lateral side includes a plurality ofinwardly (i.e. towards central tooth 32) canted teeth 34. Conversely,the right lateral teeth 36 are also inwardly canted toward the centralisosceles tooth 32. Both of the left lateral teeth 34 and right lateralteeth 36 are formed substantially as right triangles with the rightangle denoted by p. Actually p can be slightly greater than 90° toprovide a positive tooth rake when cutting.

The hypotenuse leg H of each tooth 34 and 36 is outboard with respect toits vertical leg V. As shown, when p is greater than 90°, leg V slopestowards the centerline CL providing a positive rake. In this manner,teeth 34 and 36 on opposite sides of the central tooth 32 “oppose” eachother when cutting. In cutting, FIG. 5A shows the blade poised andoriented tangential to the bone and the teeth perpendicular to thecenter line CL. FIG. 5B shows the cut after progress has been made inthe cut. The cut has been exaggerated to explain the effect.

The kerf 33 is actually V shaped about central tooth 32. As the rightside teeth 36 cuts (FIG. 5B), the left side teeth 34 are cooling andcleaning. As shown, the last tooth 36 has just finished cutting and thetooth labeled 34 is about to begin a cut. In effect, each toothprogressively takes a small cut 31 on each oscillatory stroke from thecenter then laterally outwards. This can be viewed as “progressivestaircasing” with the stairs 31 being removed one at a time. Statedalternatively, FIG. 5B shows a blade 30 in an advanced stroke ofoscillation where the staircase of material on the left side of thecenter tooth 32 has already been removed (in an earlier stroke). Thenthe blade goes into this advanced stroke and has just completelyfinished this stroke where tooth 36 has stopped its leftward or inwardmotion and this progressive staircase looking kerf has been formed. Ascan be envisioned, when the left side teeth 34 are working, the rightside teeth 36 are cooling and being cleaned of chips. A very slight Vshaped kerf is formed in practice.

The active cutting tip 6 is the end of the vertical leg V where itcontacts leg H. The central tooth 32 is optional. Note the teeth in theFIG. 3 embodiment also terminate along a tangent line T which is atright angles to the centerline CL.

With respect to FIG. 4, it is to be observed that the proximal end ofthe FIG. 4 version has not been shown. This is due to the fact that itcould be accommodated by many commercially available or by either theFIG. 1 or the FIG. 2 variants and will not be belabored here. However,the distal end 8 of the FIG. 4 version bears some differences which needto be addressed. This version 40 is distinguished from the first version10 and second version 30 by including a plurality of outwardly opposedteeth.

More specifically, the centerline CL of the FIG. 4 version 40 serves asa line of demarcation between the left side teeth 44 and the right sideteeth 46. The centerline CL, when bisecting between the left side teeth44 and the right side teeth 46, passes through a central isosceles void42 (i.e. the absence of a central tooth). The tooth structure 44 and 46is similar to the FIGS. 2 and 3 structure. However, the hypotenuse leg Hof these triangles has been transposed 180 so that this leg now facesthe central isosceles void 42 and the vertical leg V is canted slightlyto the “outside”, i.e. away from the center line CL and center isoscelesvoid 42, providing a negative rake. Using this structure, it is possibleto appreciate that the teeth 44 and 46 according to this version workopposite from the teeth 44 and 46 shown in FIGS. 2 and 3. However, allteeth in all versions are substantially “flat-top” configured, i.e., thetips stop at the tangent T perpendicular to the center line CL. Note thetip 48 of the outermost teeth 44 and 46 extend beyond the side edges 20c. The aggressive cutting pattern of the blade 40 shown in FIG. 4 hasexcellent chip clearing properties analogous to FIG. 5B, but oppositetherefrom.

Prior art FIGS. 6A and 6B show the effect of cutting teeth on a curvesuch that the radius r falls between the oscillatory axis 0 and thedistal end 8. In use, only very few teeth actually do the cutting workand the cutting is not progressively advanced. As “r” getslarger—approaching the “flat-top” structure preferred in the instantinvention, more teeth get progressively involved in the cutting. As showin FIG. 6B, tooth contact is not progressive as in FIG. 5B.

Moreover, having thus described the invention, it should be apparentthat numerous structural modifications and adaptations may be resortedto without departing from the scope and fair meaning of the instantinvention as set forth hereinabove and as claimed hereinbelow.

Alternative Embodiments of Surgical Saw Blades

The top plan view of FIG. 7 illustrates another embodiment or species ofthe present invention wherein the surgical saw blade 50 has a toothstructure comprising a center tooth 52 defining a “whale shaped” toothformed of two opposing right triangles 56 and 58 having an axiallyextending centerline or a centrally positioned long axis 62 of thesurgical saw blade passing there through.

The surgical saw blade 50 includes a proximal end 66 configured tocouple to a surgical bone saw. The surgical saw blade 50 includes adistal end 74 having at least one pair of teeth 56 and 58 for cuttingbone. The at least one pair of teeth 56 and 58 having tips areconfigured to be adjacent to each other and each tooth is configured asa right triangle with a hypotenuse which is oriented at least one oftowards and away from the centrally positioned long axis. The one tooth56 has a hypotenuse 80 which is oriented at least one of towards andaway from the centrally positioned long axis. The other of the pair ofteeth 58 is configured as a right triangle with a hypotenuse 86 which isoriented in a direction opposite to the hypotenuse of the one tooth 56of the pair of teeth. The tips of the teeth 56 and 58 are arrayedsubstantially on a tangent perpendicular to the centrally positionedlong axis 62. The distal end 74 has extending from each of the pair ofteeth 56 and 58 at least one additional tooth 90 having a tip forcutting bone which is substantially identically shaped as a righttriangle including a hypotenuse and an angle opposite the hypotenusewith a hypotenuse which is oriented in the same direction as thehypotenuse of the adjacent tooth defining the pair of teeth. The tips ofall of the teeth 56, 58 and 90 are arrayed substantially on a tangentperpendicular to the centrally positioned long axis.

In FIG. 7, this species of the surgical saw blade has a pair of opposedteeth 56 and 58 and five additional teeth 90 having tips extending fromeach of the pair of teeth 56 and 58. The proximal end 66 has a hub thatis configured to be driven by a saw having a single driving pin.

The top plan view of FIG. 8 illustrates yet another embodiment orspecies of the present invention wherein the surgical saw blade 100 hasa tooth structure comprising a center tooth 102 defining a “whaleshaped” tooth formed of two opposing right triangles 106 and 108 havingan axially extending centerline or a centrally positioned long axis 112of the surgical saw blade passing there through.

The surgical saw blade 100 includes a proximal end 116 configured tocouple to a surgical bone saw. The surgical saw blade 100 includes adistal end 120 having at least one pair of teeth 106 and 108 having tipsfor cutting bone. The at least one pair of teeth 106 and 108 areconfigured to be adjacent to each other and each tooth is configured asa right triangle with a hypotenuse which is oriented at least one oftowards and away from the centrally positioned long axis. The one tooth106 has a hypotenuse 124 which is oriented at least one of towards andaway from the centrally positioned long axis. The other of the pair ofteeth 108 is configured as a right triangle with a hypotenuse 128 whichis oriented in a direction opposite to the hypotenuse of the one tooth106 of the pair of teeth. The tips of the teeth 106 and 108 are arrayedsubstantially on a tangent perpendicular to the centrally positionedlong axis 112. The distal end 116 has extending from each of the pair ofteeth 106 and 108 at least one additional tooth 132 having a tip forcutting bone which is substantially identically shaped as a righttriangle including a hypotenuse and an angle opposite the hypotenusewith a hypotenuse which is oriented in the same direction as thehypotenuse of the adjacent tooth defining the pair of teeth. The tips ofall of the teeth 106, 108 and 132 are arrayed substantially on a tangentperpendicular to the centrally positioned long axis.

In FIG. 8, this species of the surgical saw blade has a pair of opposedteeth 106 and 108 and four additional teeth 132 having tips extendingfrom each of the pair of teeth 106 and 108. The proximal end 116 has ahub that is configured to be driven by a saw having a multiple pindriver.

The top plan view of FIG. 9 illustrates still yet another embodiment orspecies of the present invention wherein the surgical saw blade 200 hasa tooth structure comprising a center tooth 202 defining a “whaleshaped” tooth formed of two opposing right triangles 206 and 208 havingan axially extending centerline or a centrally positioned long axis 212of the surgical saw blade passing there through.

The surgical saw blade 200 includes a proximal end 216 configured tocouple to a surgical bone saw. The surgical saw blade 200 includes adistal end 220 having at least one pair of teeth 206 and 208 having tipsfor cutting bone. The at least one pair of teeth 206 and 208 areconfigured to be adjacent to each other and each tooth is configured asa right triangle with a hypotenuse which is oriented at least one oftowards and away from the centrally positioned long axis. The one tooth206 has a hypotenuse 224 which is oriented at least one of towards andaway from the centrally positioned long axis. The other of the pair ofteeth 208 is configured as a right triangle with a hypotenuse 228 whichis oriented in a direction opposite to the hypotenuse of the one tooth206 of the pair of teeth. The tips of the teeth 206 and 208 are arrayedsubstantially on a tangent perpendicular to the centrally positionedlong axis 212. The distal end 216 has extending from each of the pair ofteeth 206 and 208 at least one additional tooth 232 having a tip forcutting bone which is substantially identically shaped as a righttriangle including a hypotenuse and an angle opposite the hypotenusewith a hypotenuse which is oriented in the same direction as thehypotenuse of the adjacent tooth defining the pair of teeth. The tips ofall of the teeth 206, 208 and 232 are arrayed substantially on a tangentperpendicular to the centrally positioned long axis.

In FIG. 9, this species of the surgical saw blade has a pair of opposedteeth 206 and 208 and two additional teeth 232 extending from each ofthe pair of teeth 206 and 208. The proximal end 216 has a hub that isconfigured to be driven by a saw having a multiple pin driver.

The top plan view of FIG. 10 illustrates yet still another embodiment orspecies of the present invention wherein the surgical saw blade 300 hasa tooth structure comprising a center tooth 302 defining a “whaleshaped” tooth formed of two opposing right triangles 306 and 308 havingan axially extending centerline or a centrally positioned long axis 312of the surgical saw blade passing there through.

The surgical saw blade 300 includes a proximal end 316 configured tocouple to a surgical bone saw. The surgical saw blade 300 includes adistal end 320 having at least one pair of teeth 306 and 308 havingtips, for cutting bone. The at least one pair of teeth 306 and 308 areconfigured to be adjacent to each other and each tooth is configured asa right triangle with a hypotenuse which is oriented at least one oftowards and away from the centrally positioned long axis. The one tooth306 has a hypotenuse 324 which is oriented at least one of towards andaway from the centrally positioned long axis. The other of the pair ofteeth 308 is configured as a right triangle with a hypotenuse 328 whichis oriented in a direction opposite to the hypotenuse of the one tooth306 of the pair of teeth. The tips of the teeth 306 and 308 are arrayedsubstantially on a tangent perpendicular to the centrally positionedlong axis 212. The distal end 216 has extending from each of the pair ofteeth 306 and 308 at least one additional tooth 332 having a tip forcutting bone which is substantially identically shaped as a righttriangle including a hypotenuse and an angle opposite the hypotenusewith a hypotenuse which is oriented in the same direction as thehypotenuse of the adjacent tooth defining the pair of teeth. The tips ofall of the teeth 306, 308 and 332 are arrayed substantially on a tangentperpendicular to the centrally positioned long axis.

In FIG. 10, this species of the surgical saw blade has a pair of opposedteeth 306 and 308 and two additional teeth 332 having tips extendingfrom each of the pair of teeth 306 and 308. The proximal end 316 has ahub that is configured to be driven by a saw having a single pin driver.

As discussed above in connection with FIG. 7, the distal end 74 ofsurgical saw blade 50 has extending from each of the pair of teeth 56and 58 has at least one additional tooth 90 for cutting bone which issubstantially identically shaped as a right triangle as the teeth 56 and58 including a hypotenuse and an angle opposite the hypotenuse with thehypotenuse oriented in the same direction as the hypotenuse of theadjacent tooth 56 or 58 defining the pair of teeth. All of the tips ofall of the teeth 56, 58 and 90 are arrayed substantially on a tangentperpendicular to the centrally positioned long axis.

As illustrated in FIG. 7, the number of additional teeth can be a numberfor at least two additional teeth having tips to five additional teethhaving tips.

In the species of FIGS. 7 through 10, the surgical saw blade illustratedtherein are for use in combination with a surgical bone saw. In FIG. 8,for example, the surgical saw blade 100 comprises a proximal end 116which is configured to couple to a surgical bone saw. The surgical sawblade 100 includes a distal end 120 having a plurality of substantiallyidentical teeth having tips for cutting bone. Each of the plurality ofteeth end in a tip distally.

The surgical saw blade includes a centrally positioned long axis 112extending between the proximal end 116 and the distal end 120. At thedistal end 120, the a plurality of substantially identical teeth forcutting bone include at least one pair of teeth 106 and 108 for cuttingbone which are configured to be adjacent to each other and wherein oneof the pair of teeth, tooth 106, has a hypotenuse 124 which is orientedat least one of towards and away from the centrally positioned long axis112. The other of the pair of teeth, tooth 108, has a hypotenuse 128which is oriented in a direction opposite to the hypotenuse 128 of theone of the pair of teeth 106 and the tips thereof are arrayedsubstantially on a tangent perpendicular to the centrally positionedlong axis.

The distal end 120 has extending from each of the pair of teeth 106 and108 at least one additional tooth 132 for cutting bone which issubstantially identically shaped as a right triangle including ahypotenuse and an angle opposite the hypotenuse with a hypotenuse whichis oriented in the same direction as the hypotenuse of its adjacenttooth defining the pair of teeth 106 and 108. The tips of all of theteeth 106, 108 and 132 are arrayed substantially on a tangentperpendicular to the centrally positioned long axis.

As illustrated in FIGS. 7 through 10, the at least one additional toothmay be a single tooth having a tip or a number of teeth having tipswhich is at least two additional teeth to five additional teeth. Each ofthe additional teeth, teeth 132 in FIG. 8 being exemplary, aresubstantially identically shaped as a right triangle including ahypotenuse and an angle opposite the hypotenuse and the hypotenusethereof is oriented in the same direction as the hypotenuse of theadjacent tooth of the pair of teeth 106 and 108, respectively. The tipsof all of the teeth are arrayed substantially on a tangent perpendicularto the centrally positioned long axis. By having all of the tips of theteeth configured to be placed substantially on a tangent which isperpendicular to a radial line extending from the center line of thepower tool cutting axis that bisects the arc of travel within which theblade travels represented by the centrally extending long axisillustrated in FIGS. 7 through 10, the teeth are enabled to contact thebone to be cut and thereby and provide better tracking of the surgicalsaw blade when forming a kerf in the bone, as such, the teeth cut bothprogressively and sequentially as the kerf begins to form to providefaster aggressive cutting and efficient chip removal.

In FIGS. 7 through 10, the angle opposite each hypotenuse is greaterthan 90°.

Each of the species of the surgical saw blade illustrated in FIGS. 7through 10 can be used in a method of cutting bone. The method comprisesthe steps of: a) providing a surgical saw blade having a proximal endconfigured to couple to a surgical bone saw, a distal end having aplurality of substantially identical teeth having tips for cutting bone,each of the plurality of teeth ending in a tip distally and a centrallypositioned long axis between the proximal end and the distal end andwherein said distal end has a plurality of substantially identical teethhaving tips for cutting bone including at least one pair of teeth forcutting bone which are configured to be adjacent to each other andwherein one of the pair of teeth has a hypotenuse which is oriented atleast one of towards and away from the centrally positioned long axisand the other of said pair of teeth has a hypotenuse which is orientedin a direction opposite to the hypotenuse of the one of the pair ofteeth and wherein the tips are arrayed substantially on a tangentperpendicular to the centrally positioned long axis, and wherein saiddistal end has extending from each of said pair of teeth at least oneadditional tooth having a tip for cutting bone which is substantiallyidentically shaped as a right triangle including a hypotenuse and anangle opposite the hypotenuse with a hypotenuse which is oriented in theas the hypotenuse of the adjacent tooth defining the pair of teeth andwherein the tips of the additional teeth are arrayed substantially on atangent perpendicular to the centrally positioned long axis; b) couplingthe surgical saw blade to a surgical saw; c) actuating the surgical sawwith the coupled saw blade; and d) cutting the bone.

The method may include using a surgical saw blade wherein the additionalnumber of teeth of the saw blade provided in step a) are at least twoadditional teeth having tips.

The method may include using a surgical saw blade wherein the additionalnumber of teeth of the saw blade provided in step a) are between atleast two additional teeth having tips and five additional teeth havingtips.

The method may include using a surgical saw blade wherein the angleopposite each hypotenuse of the teeth provided in step a) is greaterthan 90°.

The structures of the surgical saw blades illustrated in FIGS. 7 through10 provide a surgeon with several variations of surgical saw blades foruse in cutting bone as part of a surgical procedure or surgicaloperation. Specifically, the structure of each of the distal ends of thesurgical saw blades of FIGS. 7 through 10 enable the tips of the teeththereof to contact the bone to be cut thereby and to provide bettertracking of the surgical saw blade when forming a kerf in the bone. Assuch, the teeth cut both progressively and sequentially as the kerfbegins to form to provide faster aggressive cutting and efficient chipremoval.

If a faster or more rapid cutting of the bone is desired during asurgical procedure, the surgeon may elect to use the surgical saw bladeof FIGS. 7 and 8 which have more teeth available to provide fasteraggressive cutting and efficient chip removal.

If a more controlled or slower cutting of the bone is desired during asurgical procedure, the surgeon may elect to use the surgical saw bladesof FIGS. 9 and 10 which have a lower number of teeth to provide a morecontrolled aggressive cutting and efficient chip removal.

Lubricious Surface Treatments for Surgical Saw Blades

The coefficient of friction between a surgical saw blade, the bone to becut and a surgical saw cutting guide, if a cutting guide is used duringa surgical procedure, may affect the quality of the final bone cut dueto possible sticking or lack of smooth movement of the surgical sawblade during a surgical procedure. It is envisioned that a lubricioussurface treatment, such as a coating could be applied to the surgicalsaw blades, described herein, to reduce the coefficient of frictionbetween a surgical saw blade, the bone to be cut and a surgicalaccessory, such as for example a surgical saw blade cutting guide.

In order to increase the performance of a surgical saw blade during asurgical procedure, a lubricious surface treatment and or coatingmaterial having a composition capable of decreasing the coefficient offriction between a surgical saw blade, the bone to be cut and a surgicalaccessory is applied to the distal end of the surgical saw bladeincluding the teeth that would be in contact with bone or bone fragmentsduring cutting. This results in a reduction of the coefficient offriction on the outer surface of the saw blade.

In the preferred embodiment, the lubricious surface treatment and orcoating material has a Vickers hardness number (HV) of about 820 orabove. The coefficient of friction of a surgical saw blade that isuntreated or uncoated with a lubricious surface treatment and or coatingmaterial is in the range of about 0.25 or more on/against steel. When alubricious surface treatment and or coating material is applied to thesurgical saw blade, using coating techniques the coefficient of frictionis lowered to about 0.8 to about 0.20 on/against steel, depending on thecomposition and physical characteristics of the lubricious surfacetreatment and or coating material.

The lower coefficient of friction of the lubricious surface treatmentand or coating of this invention gives the surgical saw blades asignificantly enhanced ability to glide easily between the bone beingcut, tissue that comes in contact with the surgical saw blade andinterproximal contact between the surgical saw blade and surgicalaccessory contacted by the surgical saw blade during a procedure suchas, for example, a cutting guide.

The following are examples of lubricious surface treatment and orcoating materials that can be used to practice this invention.

2EXAMPLES Surface Treatment/ Physical Coating Material CompositionDescription Characteristics Composite Diamond Diamond particlesHardness, corrosion resistance, abrasion resistance Thermal/PlasmaMolten Ceramic Permanent non-Spray Ceramic stick, chemical resistant,non-wetting; FDA approved Low-Temp/PVD/CVD Zirconia Nitride,Titanium-Hardness, self-Matrix Carbo Nitride, Titanium lubricating, lowOxide, Titanium Nitride or friction; Chromium Oxide Low-temperaturePhysical Vapor Deposition or Chemical Vapor Deposition Plasma/IonLow-temperature surface Hardness, self-Nitriding modification of baselubricating, low Stainless Steel friction

The lubricious surface treatment and or coating material may have aselected thickness. If the lubricious surface treatment and or coatingmaterial is applied by vacuum deposition or vapor deposition, e.g. PVD,the thickness may be in the order of a few microns (1 .mu.m to 10.mu.m). On the other hand, if the lubricious surface treatment and orcoating material is applied by dipping, spraying, a laminated coatingprocedures or is applied using other coating procedures known to thoseskilled in the art, the thickness may be in a range of the order ofabout 1 mil to about 15 mils.

The examples disclosed herein are intended to cover such applicationsdiscussed herein, and it is envisioned that other uses of a surgical sawblade having the structure disclosed and taught herein, including theuse of a lubricious surface treatment and or coating material coatedthereon, will become apparent to those skilled in the art and all suchuses are envisioned to be within the teachings and scope of the presentinvention.

All such uses, variations, modifications and the like are alsoanticipated to be within the scope of this invention.

1. A surgical saw blade for penetrating bone when said surgical sawblade is operatively coupled to an oscillatory power tool, comprising: asurgical saw blade having a proximal end and a distal end; said proximalend having a hub for attachment to an oscillatory power tool for drivingengagement thereby; said distal end having a plurality substantiallyidentically shaped cutting teeth ending in a distal tip configured to beplaced substantially on a tangent which is perpendicular to a radialline extending from the center line of the power tool cutting axis thatbisects the arc of travel within which the blade travels such that saidteeth contact the bone to be cut thereby to provide better tracking ofsaid surgical saw blade when forming a kerf in the bone, whereupon saidteeth cut both progressively and sequentially as the kerf begins to formto provide faster aggressive cutting and efficient chip removal; and alubricious coating material having a Rockwell hardness of about 65 toabout 90 being applied to the outer surface of the surgical saw blade.2. The surgical saw blade of claim 1 wherein said distal end hasextending from each of said pair of teeth at least two additional teethfor cutting bone each of which are substantially identically shaped as aright triangle including a hypotenuse and an angle opposite thehypotenuse with the hypotenuse is oriented in the same direction as thehypotenuse of the adjacent tooth defining said pair of teeth and whereinthe tips of all of the teeth are arrayed substantially on a tangentperpendicular to the centrally positioned long axis.
 3. The surgical sawblade of claim 1 wherein said distal end has extending from each of saidpair of teeth at least three additional teeth for cutting bone each ofwhich are substantially identically shaped as a right triangle includinga hypotenuse and an angle opposite the hypotenuse with the hypotenuse isoriented in the same direction as the hypotenuse of the adjacent toothdefining said pair of teeth and wherein the tips of all of the teeth arearrayed substantially on a tangent perpendicular to the centrallypositioned long axis.
 4. The surgical saw blade of claim 1 wherein saiddistal end has extending from each of said pair of teeth at least fouradditional teeth for cutting bone each of which are substantiallyidentically shaped as a right triangle including a hypotenuse and anangle opposite the hypotenuse with the hypotenuse is oriented in thesame direction as the hypotenuse of the adjacent tooth defining saidpair of teeth and wherein the tips of all of the teeth are arrayedsubstantially on a tangent perpendicular to the centrally positionedlong axis.
 5. The surgical saw blade of claim 1 wherein said distal endhas extending from each of said pair of teeth at least five additionalteeth for cutting bone each of which are substantially identicallyshaped as a right triangle including a hypotenuse and an angle oppositethe hypotenuse with the hypotenuse is oriented in the same direction asthe hypotenuse of the adjacent tooth defining said pair of teeth andwherein the tips of all of the teeth are arrayed substantially on atangent perpendicular to the centrally positioned long axis.
 6. Thesurgical saw blade of claim 1 wherein the coefficient of friction of thelubricious coating material is in the range of about 0.08 to about 0.25.7. The surgical saw blade of claim 1 wherein the lubricious coatingmaterial is selected from a group consisting of Composite Diamond, aTeflon/Nickel Composite, an Inorganic Powder/Nickel, a Fluoropolymer, aFusion bonded fluoropoly, a Thermal Spray Polymer, a PVD Matrix,polytetrafluoroethylene, Fluorinated Ethylene Propylene,Perfluoroalkoxy, Ethylene/Tetrafluoroethylene Copolymer andAnti-microbial Material.